<template>
  <div class="channel-edit">
    <van-cell :border="false">
      <div slot="title" class="title-text">我的频道</div>
      <van-button
        class="edit-btn"
        size="mini"
        round
        type="danger"
        plain
        @click="isEdit = !isEdit"
        >{{ isEdit ? '完成' : '编辑' }}</van-button
      >
    </van-cell>
    <van-grid class="my-grid" :gutter="10">
      <van-grid-item
        icon="clear"
        class="grid-item"
        v-for="(channel, index) in myChannels"
        :key="index"
        :text="channel.name"
        @click="onMyChannelClick(channel, index)"
      >
        <van-icon
          v-show="isEdit && !fiexdChannels.includes(channel.id)"
          slot="icon"
          name="clear"
        >
        </van-icon>
        <span
          class="text"
          :class="{ active: index === activeIndex }"
          slot="text"
          >{{ channel.name }}</span
        >
      </van-grid-item>
    </van-grid>
    <van-cell :border="false">
      <div slot="title" class="title-text">频道推荐</div>
    </van-cell>

    <van-grid class="recomment-grid" :gutter="10">
      <!-- 给推荐频道中的频道注册点击事件 -->
      <van-grid-item
        icon="plus"
        class="grid-item"
        v-for="channel in recommendChannele"
        :key="channel.id"
        :text="channel.name"
        @click="onAddChannel(channel)"
      />
    </van-grid>
  </div>
</template>

<script>
import {
  getAllChannels,
  addUserChannel,
  deleteUserChannel
} from '@/api/channel.js'
// 在添加频道的方法中根据 user 判断用户登录与否
import { mapState } from 'vuex'
// 处理未登录模块，导入封装的本地存储模块
import { setItem } from '@/utils/storage.js'

export default {
  name: 'ChannelEdit',
  props: {
    myChannels: {
      type: Array,
      required: true
    },
    activeIndex: {
      type: Number,
      required: true
    }
  },
  data() {
    return {
      // 所有频道
      allChannels: [],
      // 控制编辑状态
      isEdit: false,
      // 不需要编辑、删除的频道
      fiexdChannels: [0]
    }
  },
  created() {
    this.loadAllChannels()
  },
  methods: {
    async loadAllChannels() {
      try {
        const { data } = await getAllChannels()
        this.allChannels = data.data.channels
      } catch (error) {
        console.log(error)
        this.$toast('获取所有频道数据失败')
      }
    },
    // 在添加频道事件处理函数中
    async onAddChannel(channel) {
      this.myChannels.push(channel)
      // 数据持久化处理
      if (this.user) {
        // 已登录，把数据请求接口放到服务器
        // console.log('1')
        try {
          await addUserChannel({
            // 频道 ID
            id: channel.id,
            // 序号
            seq: this.myChannels.length
          })
        } catch (error) {
          this.$toast('保存失败，请稍后再试')
        }
      } else {
        // 未登录，把数据存储到本地
        setItem('TOUTIAO_CHANNELS', this.myChannels)
      }
    },

    // 切换频道
    onMyChannelClick(channel, index) {
      if (this.isEdit) {
        // 如果是固定频道，则不删除
        if (this.fiexdChannels.includes(channel.id)) {
          return
        }
        // 编辑状态，执行删除频道
        // 删除频道项(当前页面)

        this.myChannels.splice(index, 1)

        // 如果要删除的激活频道之前的频道，则更新激活的频道项
        // 参数1：要删除的元素的开始索引
        // 参数2：要删除的个数，如果不指定，则从参数 1 开始一直删除
        if (index <= this.activeIndex) {
          // 让激活频道索引 - 1
          this.$emit('update-active', this.activeIndex - 1, true)
        }
        // 处理持久化操作
        this.deleteChannel(channel)
      } else {
        // 非编辑状态，指向切换频道
        this.$emit('update-active', index, false)
      }
    },

    // 删除频道
    async deleteChannel(channel) {
      try {
        if (this.user) {
          await deleteUserChannel(channel.id)
        } else {
          // 未登录，将数据更新到本地
          setItem('TOUTIAO_CHANNELS', this.myChannels)
        }
      } catch (error) {
        this.$toast('操作失败，请稍后重试')
      }
    }
  },
  computed: {
    recommendChannele() {
      const channels = []
      this.allChannels.forEach((channel) => {
        // 使用 find 遍历数组，找到满足条件的元素项
        const ret = this.myChannels.find((userChannels) => {
          return userChannels.id === channel.id
        })
        // 如果我的频道中不包括该频道项，则收集到推荐频道中
        if (!ret) {
          channels.push(channel)
        }
      })
      return channels
    },
    ...mapState(['user'])
  }
}
</script>

<style scoped lang="less">
.channel-edit {
  padding: 85px 0;

  .title-text {
    font-size: 32px;
    color: #333;
  }

  .edit-btn {
    width: 104px;
    height: 48px;
    font-size: 26px;
    color: #f85959;
    border: 1px solid #f85959;
  }

  /deep/ .grid-item {
    width: 160px;
    height: 86px;
    .van-grid-item__content {
      white-space: nowrap;
      background-color: #f4f5f6;

      .van-grid-item__text,
      .text {
        font-size: 22px;
        color: #222;
        margin-top: 4px !important;
      }
      .van-grid-item__icon-wrapper {
        position: unset;
      }

      .active {
        color: red;
      }
    }
  }

  /deep/ .my-grid {
    .grid-item {
      .van-icon-clear {
        position: absolute;
        right: -10px;
        top: -10px;
        font-size: 30px;
        color: #cacaca;
        z-index: 2;
      }
    }
  }

  /deep/ .recomment-grid {
    .grid-item {
      width: 160px;
      height: 86px;
      .van-grid-item__content {
        flex-direction: row;

        .van-icon-plus {
          font-size: 22px;
          line-height: 22px;
          margin-right: 6px;
        }
      }
    }
  }
}
</style>
